K&N Air Filter: Testing for MPG Change, Do they help? Hinder? I attempt to find out Options

[NevynPA]

So, FSUSpectra was kind enough to send me his K&N air filter that he wasn't using for me to test and shed some light on the big question:


Does a K&N air filter help you get better MPG?


There are two sides to this, and while my testing won't put the question to rest once and for all, it will at least provide some results that will hopefully be useful.

I've uploaded the videos I have so far to YouTube and created a playlist for them:

http://www.youtube.com/playlist?list=PL05C4F32D9B4E1CB0

I have still photos as well, and they will be hosted (elsewhere) and posted (here).



Plaintiff: K&N filters are bad for MPG.

Argument: K&N designed their air filters to be more free-flowing than the conventional air filter. By allowing more air into the engine, the ECU then adjusts the amount of fuel injected to compensate for the greater mass of air in order to maintain the proper air/fuel ratio. More fuel being injected means more fuel burned, thus lower MPG.

Defendant: K&N filters are good for MPG.

Argument: With the additional air being brought in by the engine, it develops more power. This added boost of power allows the engine to run more efficiently, increasing MPG. The extra power allows the engine to be able to work efficiently in higher gears (4th/5th) at a lower speed, thus delaying the need for a downshift to a less efficient gear.

Evidence:

[slowgls]

Cant wait to see the results. Good work.

[Silentwolf]

Should be interesting. Lot to be said for being able to shift at a lower rpm to a higher gear. I'm able to accelerate from 10mph with much less effort now with the CAI.

[popeye]

I'm not interested in mpgs, I just like the sound I get from having a less restricted intake lol! j/k, it'll be interesting to see what the results are. You'll have to post them for peer review first though

[Elantrick]

I My results after installing a short intake are less mpg. The engine probably makes more power, but I just like the sound so I am not getting as good milage

[NevynPA]

If you "like the sound" then you're in the pedal WAY too deep, too often to be doing it for MPG. I've got a 100% stock airbox. The sound is different, but only barely. I'll hopefully get the stills up today.

[FSUspectra]

Thanks again for taking this on (although I'm sure it's not too much hair off your back ). Looking forward to the results.

[benman]

Stumbled upon this topic searching for something else today -- so did you ever draw any conclusions?

[NevynPA]

I have lots of data, and little time to compile it. My laptop is working again and that's where all my photos are - I just have to get them up and hosted, organized, my fill-ups charted, and it all written out.

Quick thought is no, it's no different for MPG - but it does change the performance of the car.

[benman]

Coincidentally, I got home to find that the K&N drop-in I'd ordered from Amazon (yes, though the EC Affiliate link) had arrived. I dropped it in this morning (and also removed the PZEV charcoal filter) before my morning commute.

Anecdotal evidence this morning is the same: there was no discernable change in fuel economy at various checkpoints along the way, but a world of difference in performance on the hills (especially the very steep one that begins my commute).

[jamhandman]

hmmm.... maybe I'll get one for mine and the wife's accent We do drive on a LOT of hills here. I'm just not too comfortable I'll maintain the filter correctly. Hmmm... maybe..

[Spectre]

I had bought an accord CAI for my car and have been having a lot of trouble getting it on. I just now noticed this thread and I have a K&N drop in filter. Maybe I should just leave the filter in and not bother with the CAI, based on the feedback I see here.